The invention relates to a headlamp for a motor vehicle, in particular a front headlamp.
The prior art has disclosed many different principles for being able to generate predetermined light distributions using a motor vehicle headlamp. In the document WO 2015/058227 A1, a micro-projection light module is used in a motor vehicle headlamp, a light distribution in front of the motor vehicle being generated in the case of said micro-projection light module by way of a multiplicity of micro-optics. Here, a stop apparatus, by means of which it is possible to produce, for example, a low beam distribution, is provided between entrance optics and exit optics, which each comprise a multiplicity of micro-lenses.
Conventional motor vehicle headlamps on the basis of micro-production technology facilitate a highly precise generation of light distributions. However, no further light effects have been able to be generated to date using such headlamps.
It is an object of the invention to develop a motor vehicle headlamp on the basis of micro-projection technology with an additional light effect.
This and other objects are achieved by a headlamp according to the invention for a motor vehicle, such as an automobile, for example. The headlamp is preferably a front headlamp. The headlamp comprises a multi-aperture projection display with an illuminant and an planar image generator, and an array of projection lenses, wherein each projection lens is assigned to a segment of the planar image generator such that, when the array is illuminated by the illuminant, at least some of the segments are projected in front of the headlamp by the assigned projection lenses in order to produce at least one light distribution.
The headlamp according to the invention is distinguished by predetermined segments of the segments of the planar image generator being configured and arranged in relation to one another in one or more portions of the planar image generator in such a way that, when the illuminant is switched off, imagery that is perceivable by an observer is presented on the planar image generator in the case of a viewing angle of the observer in a predetermined viewing angle range toward the headlamp (i.e toward the light exit opening of the headlamp). The predetermined viewing angle range preferably comprises the viewing direction perpendicular onto the planar image generator. Depending on the configuration, the viewing angle range can be of different sizes. Optionally, the imagery can also be visible to the observer over substantially the entire angle range of 180° in front of the headlamp. In a preferred variant, the multi-aperture projection display also comprises an array of field lenses, which is arranged between the illuminant and the planar image generator, in addition to the array made of projection lenses. One or more LEDs or else, optionally, one or more laser diodes, are preferably used as illuminants in the projection display.
The headlamp according to the invention is advantageous in that the effect of visible imagery is produced in a simple manner by way of appropriately configured segments in the case of a deactivated headlamp. Here, the term “imagery” should be interpreted broadly. In particular, the imagery may contain text and/or one or more pictograms (e.g. logos) and the like. By way of example, the imagery can represent a logo and/or the lettering of a motor vehicle manufacturer.
In a particularly preferred embodiment, a multi-aperture projection display, as described in the document DE 10 2009 024 894 A1 or in the document DE 10 2011 076 083 A1, is used in the headlamp according to the invention. The entire disclosures of these documents are expressly incorporated by reference herein.
In a particularly preferred embodiment of the headlamp according to the invention, the predetermined segments are configured and arranged in relation to one another in such a way that, even when the illuminant is activated, the imagery is presented on the planar image generator at a viewing angle of the observer in a predetermined viewing angle range toward the headlamp. Here, the predetermined viewing angle range need not necessarily correspond to the aforementioned predetermined viewing angle range when the headlamp is deactivated. In particular, the predetermined viewing angle range can comprise the viewing direction perpendicular onto the planar image generator; however, the predetermined viewing angle range can also exclude a viewing angle range that contains the viewing direction perpendicular onto the planar image generator.
In a further preferred embodiment of the headlamp according to the invention, one or more of the predetermined segments each are light-opaque over their entire area or each have a transmittance of less than 100%, in particular of less than 50%, over their entire area. This variant ensures that the imagery is visible in the viewing direction perpendicular to the planar image generator, even when the illuminant is activated.
In a further variant of the headlamp according to the invention, one or more of the predetermined segments each have a light-transmitting aperture (i.e., with a transmittance of substantially 100%). Preferably, the respective predetermined segment is completely light-opaque apart from the light-transmitting aperture. In a preferred variant, the light-transmitting aperture is arranged centrally on the respective predetermined segment in a plan view. The use of light-transmitting apertures renders it possible to increase the brightness of certain regions (so-called hotspots) in the light distribution generated by the headlamp.
In a particularly preferred variant of the headlamp according to the invention, the extent of a respective segment in the vertical and horizontal direction (i.e. in the width direction and in the height direction of the motor vehicle when the headlamp is installed) does not exceed the diameter of the assigned (round) projection lens. The diameter of the respective projection lens preferably is 2000 μm or less, in particular 1000 μm or less, for example 800 μm. The multi-aperture projection display preferably comprises 1000 to 5000 segments with assigned projection lenses in the plan view onto the planar image generator.
In one configuration of the headlamp according to the invention, the image generator comprises a transparent substrate (i.e., with a transmittance of substantially 100%) with light-opaque regions applied thereon and/or with regions with a transmittance of less than 100%, in particular of less than 50%, applied thereon. By way of example, the regions applied thereon can be formed by a chrome mask. The transparent substrate is preferably a glass substrate. The headlamp according to this variant can be produced in a simple and cost-effective manner.
In a further embodiment of the method according to the invention, the planar image generator comprises a digital image generator, in particular an LCD display (such as a TFT display, for example). This digital image generator is actuatable in such a way that the structure of the segments can be varied such that different lighting effects can be produced. Preferably, the digital image generator is actuatable in such a way that different imagery is displayable on the digital image generator, depending on the actuation thereof.
In a further variant, the headlamp according to the invention is actuatable in such a way that, upon activation of the illuminant, the projection lenses of the array, and hence also the segments, are illuminated in succession until the entire array is illuminated. By way of example, the successive illumination can be performed in the horizontal direction or in the vertical direction of the planar image generator, or else optionally in an oblique direction. Using this variant, it is possible to generate an appealing lighting effect in the form of gradually lighting up imagery.
Different light distributions can be produced using the headlamp according to the invention, depending on the configuration. In particular, a low beam distribution, a high beam distribution and/or an antiglare high beam can be generated using the multi-aperture projection display. Other types of light distributions are also possible. In the case of a low beam distribution, the segments that are not predetermined segments are embodied as a stop in each case with a predetermined light/dark boundary.
In addition to the above-described headlamp, the invention further relates to a motor vehicle, wherein the motor vehicle comprises one or more of the headlamps according to the invention, or one or more preferred variants of this headlamp.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.